Understanding Blood Pressure Readings

Updated:Dec 5,2017

What do your blood pressure numbers mean?The only way to know (diagnose) if you have high blood pressure (HBP or hypertension) is to have your blood pressure tested. Understanding your blood pressure numbers is key to controlling high blood pressure.

Healthy and unhealthy blood pressure rangesLearn what’s considered normal, as recommended by the American Heart Association.

Note: A diagnosis of high blood pressure must be confirmed with a medical professional. A doctor should also evaluate any unusually low blood pressure readings.

Enter Your Blood Pressure

Systolic
mm Hg (upper #)

Diastolic
mm Hg (lower #)

Blood pressure categoriesThe five blood pressure ranges as recognized by the American Heart Association are:

Normal blood pressureCongratulations on having blood pressure numbers that are within the normal (optimal) range of less than 120/80 mm Hg. Keep up the good work and stick with heart-healthy habits like following a balanced diet and getting regular exercise.

ElevatedElevated blood pressure is when readings are consistently ranging from 120-129 systolic and less than 80 mm Hg diastolic. People with elevated blood pressure are likely to develop high blood pressure unless steps are taken to control it.

Hypertension Stage 1Hypertension Stage 1 is when blood pressure is consistently ranging from 130-139 systolic or 80-89 mm Hg diastolic. At this stage of high blood pressure, doctors are likely to prescribe lifestyle changes and may consider adding blood pressure medication.

Hypertension Stage 2Hypertension Stage 2 is when blood pressure is consistently ranging at levels of 140/90 mm Hg or higher. At this stage of high blood pressure, doctors are likely to prescribe a combination of blood pressure medications along with lifestyle changes.

Hypertensive crisisThis is when high blood pressure requires medical attention.If your blood pressure readings suddenly exceed 180/120 mm Hg, wait five minutes and test again. If your readings are still unusually high, contact your doctor immediately. You could be experiencing a hypertensive crisis. If your blood pressure is higher than 180/120 mm Hg and you are experiencing signs of possible organ damage such as chest pain, shortness of breath, back pain, numbness/weakness, change in vision, difficulty speaking, do not wait to see if your pressure comes down on its own. Call 9-1-1.

Your blood pressure numbers and what they mean Your blood pressure is recorded as two numbers:

Systolic blood pressure (the upper number) — indicates how much pressure your blood is exerting against your artery walls when the heart beats.

Diastolic blood pressure (the lower number) — indicates how much pressure your blood is exerting against your artery walls while the heart is resting between beats.

Which number is more important?Typically, more attention is given to systolic blood pressure (the top number) as a major risk factor for cardiovascular disease for people over 50. In most people, systolic blood pressure rises steadily with age due to the increasing stiffness of large arteries, long-term build-up of plaque and an increased incidence of cardiac and vascular disease.

However, elevated systolic or diastolic blood pressure alone may be used to make a diagnosis of high blood pressure. And, according to recent studies, the risk of death from ischemic heart disease and stroke doubles with every 20 mm Hg systolic or 10 mm Hg diastolic increase among people from age 40 to 89.

Why blood pressure is measured in mm HgThe abbreviation mm Hg means millimeters of mercury. Why mercury? Mercury was used in the first accurate pressure gauges and is still used as the standard unit of measurement for pressure in medicine.